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Mineralisation

Posted: Fri Jun 07, 2019 8:20 pm
by Ladybird66
Last couple of times out I’ve re-visited some of my original field permissions. Quick and easy to get to, easy parking etc just to get me back into some detecting.
I remembered that one field had that enormously gas pipe laid through it. Didn’t find anything in it first time around but wondered if the trenching might have brought something up.
All set up, changed nothing from the previous outing but couldn’t believe what I was hearing. Iron on every sweep. In All Metal, got so fed up with it I turned it off but could hear it nulling constantly.
Was reluctant to change any setting in the field so put up with it. Dug every squeak and whisper, nearly all iron, nails etc. Readings up to 24 on the NOX.
Worried there was something wrong with the NOX I tested it when I got home. Perfect. Then later I remembered I’d had the same problem when I first detected some of those fields and someone explained it was high mineralisation in the soil and it happened when ground was left uncultivated for many years.
Has anyone got any experience or knowledge of this ? I mention it because I thought some might experience the same conditions and wonder what heck was going on.

Re: Mineralisation

Posted: Fri Jun 07, 2019 9:51 pm
by erm1969
Hi Ladybird, what settings are you using on your Equinox? Some of my local fields are heavily mineralised, but I think that is due to the local geology, rather than lack of cultivation. I have to run with the sensitivity at 15 or 16, but still picking out thin coins at reasonable depth (Field 2). Other places I've had the sensitivity up to 24 with smooth operation.

Re: Mineralisation

Posted: Fri Jun 07, 2019 10:05 pm
by Ten pence!
The Equinox has a very capable set of controls to keep excessive falsing due to iron contamination in check, why not use them? Some of my best sites are also heavily infested with modern iron, but I don't really have any undue problems.

There is often a desire to eke out an extra millimetre or two of depth regardless of conditions, so you get all metal and slow recovery speeds and sensitivity on 20+, BAD ADVICE in my book! I can't quite work out why some want to hear all the iron under the coil, after all it can be very distracting, notch out all the small iron, up the recovery speeds and learn to listen instead of number checking, you can even turn off the iron bias as you are not trying to control the smaller stuff any longer, bigger iron is easy to pick out on the Nox's audio.

Re: Mineralisation

Posted: Sat Jun 08, 2019 1:15 am
by Ladybird66
erm1969 wrote:
Fri Jun 07, 2019 9:51 pm
Hi Ladybird, what settings are you using on your Equinox? Some of my local fields are heavily mineralised, but I think that is due to the local geology, rather than lack of cultivation. I have to run with the sensitivity at 15 or 16, but still picking out thin coins at reasonable depth (Field 2). Other places I've had the sensitivity up to 24 with smooth operation.
No trouble with my settings in Field 1 to date. Proved that everywhere else I’ve used it. Clear as a bell. Changed from Field 2 because I was picking up a lot of coke.
It is the mineralisation I am curious about. Just wondered if anyone had any clear info on it. Despite the explanation I was given I’m inclined to agree with erm, it’s got to be geological. And I must admit it didn’t occur to me to drop the sensitivity. It was clear iron signals I was getting, on every swing, not that horrible noise you get with electrical interference. I know there was iron stone mined in the general area a long time ago.
Nice to know someone else gets the same problem. I’ll remember the sens’ next time. Thanks for replies.

p.s. don’t think I missed much on previous visits.